1. Field of the Invention
The present invention relates to a novel nitrosourea derivative or a pharmaceutically acceptable acid addition salt thereof. Particularly it is concerned with a nitrosourea derivative represented by the general formula (I), ##STR1## wherein --NHR represents a 2-(1,3,4-thiadiazolyl)amino group, an amino residue of a neutral .alpha.-amino acid, or an amino residue of a neutral .alpha.-amino acid whose carboxyl group is amidated with 2-(1,3,4-thiadiazolyl)amine, or a pharmaceutically acceptable acid addition salt of the derivatives, as well as also with processes for producing the same.
2. Description of the Prior Art
There have been known many N-(2-chloroethyl)-N-nitrosourea compounds which are useful as antitumor substance of alkylating agent type. On the other hand, the present inventors have previously found that a certain amide compound prepared by condensing 2-amino-1,3,4-thiadiazole with an amino acid has a strong antitumor effect as a metabolic antagonist for nicotinic acid necessary for glycolysis which is actively taken place in cancer tissues, and have applied for a patent (Japanese Patent Application No. 128146/78).